In the previous Gbg where it could 100% reduction, Traps were plain silly. Now with 80% max, some may be seeing if traps make a difference. A short while back in one guild we had an opponent using traps,for a time. But it was obvious traps did not deter my guild at all. So they stopped.
If players are afraid of attrition, then yeah traps will deter the enemy, On the other hand if players are fearless and take attrition in stride as part of the play, no problem. smash them anyway! Plus traps do not add to VP.. So the Guild that places traps are shooting themselves as much as the opponent.
I used to worry and try hard to not get attrition, But the new GbG I had to change my strategy, and no longer prioritize numbers of fights, I really now only want to max my attrition each day. (if I can) This change in attitude frees me from the worry about attrition, and I now see attrition as a positive, rather than a negative for my Guild. The goodies won are a bonus.
(Similar to Himeji Castle, The real reward IMO are the supplies, the won goodies are all gravy !!)
all this stuff is in your head..